ami bios survival guide

8/8/2019 AMI BIOS Survival Guide

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The AMI BIOS Survival Guide

_________________________________________________________________

Edited by Jean-Paul Rodrigue

[email protected]

Contributors==================================Gordon L. Burditt ([email protected])Peter Herweijer ([email protected])Kajetan Hinner ([email protected])Piotr Karocki ([email protected])Brian Lee ([email protected])Aad Offerman ([email protected])Keith Rohrer ([email protected])Jerome Schneider ([email protected])

Cameron Spitzer ([email protected])Andy Walton ([email protected])

Version history==================================Version 1.0 to 1.3: December 1993 (initial postings)Version 2.0 to 2.4: January 1994 (the first "complete" versions)Version 2.5 and 2.6 : February 1994 (vitamin C added)Version 2.65 and 2.7: March 1994 (no cholesterol)Version 3.0: 16-04-94 (new prune-strawberry-cabbage flavour)Version 3.1: 13-05-94 (friday the 13th edition)

What's new in version 3.1 (*)

==================================- FTP archive site available for the guide.- A list of BIOS error messages (see section 2.4)- Several additions to various topics (*).

Crossposted in:==================================comp.sys.ibm.pc.hardware, comp.sys.ibm.pc.hardware.chips,comp.sys.ibm.pc.hardware.misc & comp.answers (patent pending).

(*) Archive Site==================================

The guide, along with other hardware-related FAQs, is available throughanonymous FTP at rahul.net in the pub/cameron/PC-info directory. Thedocument is compressed by Gzip, available at any GNU archive sites likegatekeeper.dec.com, in the pub/GNU directory.

What is the AMI BIOS survival guide?==================================BIOS settings are a frequent problem in several hardware relatednewsgroups. Did you ever experienced a system lock up or poorperformance and erratic behaviour due to improper BIOS settings? Haveyou ever been let in the dark by a cryptic 5 pages badly writtenmotherboard manual? The answer is probably yes. I took some initiativeand decided to edit a FAQ for the AMI BIOS (American Megatrends

Inc.). This BIOS is, I believe, the most common. The guide provides adescription of each BIOS functions (at least those we are aware of) andtips for their settings. I hope it will eventually help newbies "decipher"



BIOS settings and more advanced users "optimize" their system. It couldeven keep you from a painful visit to your local computer store!

Disclaimer and other stuff==================================This document is provided "as is". The editor and contributors take noresponsabilities for any problems, damages, humiliations, world wars or

loss of sanity resulting from improper BIOS settings. If you are in doubt,please post a question to the comp.sys.ibm.pc.hardware.chips newsgroupor refer to a competent computer technician. Messing up with somethingyou do not understand will often get you in trouble (Who doesn't knowsomeone who did?). YOU HAVE BEEN WARNED.This guide is provided as a free reference for the usenet (internet)community. You may distribute it freely as long as the contents are notaltered, no fees are asked, and references to the editor and contributorsare kept. If you are making money out of this file or posting net-wide (togroups where it does not belong) religious babblings or green card lotteryscam: may your CPU perish by electromigration!

I want to know more...==================================If you have an UNSOLVED BIOS problem not described herein, pleasepost it to related newsgroups (like comp.sys.ibm.pc.hardware.chips),NOT to the editor or the contributors. You should also have a look at theibm.pc.hardware.* Frequently Asked Questions (FTP rtfm.mit.edu;directory: /pub/usenet/news.answers/csiph-faq; filenames: part1 to part5)posted regularly. It contains a wealth of information about computerhardware. Look also in the comp.answers newsgroup for available FAQs.If you have a SOLVED problem, please send it to the editor so it can beadded to subsequent versions of this document. Your contributions orcomments will be much appreciated. If you want the most recent versionof this document, please e-mail the editor and tell what version you

currently have. If a more recent version is available, it will be fowarded.Before doing so, please look in this newsgroup for a regular posting of thisguide.If you want various technical information about AMI BIOS, you can findit at the FTP site AMERICAN.MEGATRENDS.COM. If you can affordlong distance charges, try the AMI BBS at (404) 246-8780 (or 8781, 8782,8783). There is also a shareware named AMISETUP that enables BIOSsettings and provides an on-line reference (for registered versions). It caneven let you access some settings that could not be accessed otherwise.You can find it at SIMTEL mirror sites like FTP.WUSTL.EDU orOAK.OAKLAND.EDU in the /systems/ibmpc/msdos/sysutil directory.The file name is AMISE260.ZIP.

One last thing...==================================I would like to thank the contributors to have taken some of their time towrite varied topics and provide enlightening feedbacks. Some parts of thisdocument are still incomplete and some information may be inaccurate.Your feedbacks will help this document be as accurate and up to date aspossible. I am sorry if I cannot answer to everyone or add everything thatis send to me.I would also like to thank the following persons for providing informationon specific topics: Michiel de Vries, Andy Eskilsson, Doug Hogarth,Reinhard Kirchner, Mirek Komon, Jim Kozma, Juha Laiho, Alain Lavoie,Erik Mouw, Chris Pollard, Dietrich Schmidt, Hans Schrader, Loren

Schwiebert, Dan Sobel, Dave Spensley and Dmitry Stefankov.

TABLE OF CONTENT



==================================1.0 DEFINITIONS

1.1 BIOS1.2 CMOS1.3 Chipset

2.0 POST AND ENTERING SETUP2.1 A Typical AMI BIOS POST Sequence

2.2 AMI BIOS POST Errors2.3 Other AMI BIOS POST Codes(*) 2.4 BIOS Error Messages

3.0 STANDARD CMOS SETUP4.0 ADVANCED CMOS SETUP5.0 ADVANCED CHIPSET SETUP6.0 AUTO CONFIGURATION WITH BIOS DEFAULTS7.0 AUTO CONFIGURATION WITH POWER-ON DEFAULTS8.0 CHANGE PASSWORD9.0 HARD DISK UTILITY

9.1 Hard Disk Format9.2 Auto Detect Hard Disk

9.3 Auto Interleave9.4 Media Analysis.10.0 WRITE TO CMOS AND EXIT11.0 DO NOT WRITE TO CMOS AND EXIT12.0 FREQUENTLY ASKED QUESTIONS (FAQ)

1.0 DEFINITIONS==================================1.1 BIOS: Basic Input Output System. Computer hardware has to workwith software, so it needs an interface with it. The BIOS gives thecomputer a little built-in starter kit to run the rest of softwares from floppydisks (FDD) and hard disks (HDD). The BIOS is responsible for bootingthe computer by providing a basic set of instructions. It performs all the

tasks that need to be done at start-up time: POST (Power-On Self Test,booting an operating system from FDD or HDD). Furthermore, itprovides an interface to the underlying hardware for the operating systemin the form of a library of interrupt handlers. For instance, each time akey is pressed, the CPU (Central Processing Unit) perform an interrupt toread that key. This is similar for other input/output devices (Serial andparallel ports, video cards, sound cards, hard disk controllers, etc...).Some older PC's cannot co-operate with all the modern hardware becausetheir BIOS doesn't support that hardware. The operating system cannotcall a BIOS routine to use it; this problem can be solved by replacing yourBIOS with an newer one, that does support your new hardware, or byinstalling a device driver for the hardware.

1.2 CMOS: Complementary Metal Oxide Semiconductor. To perform itstasks, the BIOS need to know various parameters (hardwareconfiguration). These are permanently saved in a little piece (64 bytes) ofCMOS RAM (short: CMOS). The CMOS power is supplied by a littlebattery, so its contents will not be lost after the PC is turned off.Therefore, there is a battery and a small RAM memory on board, whichnever (should...) loses its information. The memory was in earlier timesa part of the clock chip, now it's part of such a highly Integrated Circuit(IC). CMOS is the name of a technology which needs very low power,so the computer's battery is not too much in use. Actually there is not abattery on new boards, but an accumulator (Ni_Cad in most cases). It isrecharged every time the computer is turned on. If your CMOS is

powered by external batteries, be sure that they are in good operatingcondition. Also, be sure that they do not leak. It may damage themotherboard. Otherwise, your CMOS may suddenly "forget" its



configuration and you may be looking for a problem elsewhere. In themonolithic PC and PC/XT this information is supplied by setting the DIP(Dual-In-line Package) switches at the motherboard or peripheral cards.Some new motherboards have a technology named the Dallas Nov-Ram.It eliminates having an on-board battery: There is a 10 year lithium cellepoxyed into the chip.

1.3 Chipset: A PC consists of different functional parts on itsmotherboard: ISA (Industry Standard Architecture), EISA (EnhancedIndustry Standard Architecture) VESA (Video Enhanced StandardsAssociation) and PCI (Peripheral Component Interface) slots, memory,cache memory, keyboard plug etc... The chipset enables a set ofinstructions so the CPU can work (communicate) with other parts of themotherboard. Nowadays most of the discrete chips; PIC (ProgrammableInterrupt Controller), DMA (Direct Memory Access), MMU (MemoryManagement Unit), cache, etc... are packed together on one, two or threechips; the chipset. SETUP allows you to change the parameters withwhich the BIOS configures your chipset. Since chipsets of a differentbrand are not the same, for every chipset there is a BIOS version. Now

we have fewer and fewer chipsets which do the job. Some chipsets havemore features, some less. OPTi is such a commonly used chipset. Insome well integrated motherboards, the only components present are theCPU, the two BIOS chips (BIOS and Keyboard BIOS), one chipset IC,cache memory (DRAMs, Dynamic Random Access Memory), memory(SIMMs, Single Inline Memory Module, most of the time) and a clockchip.

2.0 POST AND ENTERING SETUP==================================When the system is powered on, the BIOS will perform diagnostics andinitialize system components, including the video system. (This isself-evident when the screen first flicks before the Video Card header is

displayed). This is commonly refered as POST (Power-On Self Test).Afterwards, the computer will proceed its final boot-up stage by callingthe operating system. Just before that, the user may interupt to have accessto SETUP.To allow the user to alter the CMOS settings, the BIOS provides a littleprogram, SETUP. Mostly setup can be entered by pressing a special keycombination (DEL, ESC, CTRL-ESC, or CRTL-ALT-ESC) at boot time(Some BIOSes allow you to enter setup at any time by pressingCTRL-ALT-ESC). The AMI BIOS is mostly entered by pressing the DELkey after resetting (CTRL-ALT-DEL) or powering up the computer. Youcan bypass the extended CMOS settings by holding the key downduring boot-up. This is really helpful, especially if you bend the CMOSsettings right out of shape and the computer won't boot properly anymore.This is also a handy tip for people who play with the older AMI BIOSes withthe XCMOS setup. It allows changes directly to the chip registers with verylittle technical explanation.

2.1 A Typical AMI BIOS POST Sequence------------------------------a) Display some basic informations about the video card like its brand,video BIOS version and video memory available.b) Display the BIOS version and copyright notice in upper middle screen.You will see a large sequence of numbers at the bottom of the screen.They refer to the BIOS serial number, version and type of chipset. (*) Forversions 1986-1991 (AMIBIOS before HI-Flesh):

Reference number: ABBB-NNNN-MMDDYY-KX, whereA = D for BIOS with Diagnostics.

= S for BIOS with Setup program.



= E for BIOS with Extended Setup program.BBB = C&T for C&T386 chipset.

= NET for C&T NEAT chipset.= 286 fpr standard 286,VLSI,G2 286 boards.= SUN for SUNTAC 286 boards.= PAQ for COMPAQ compatible 386 boards.= INT for INTEL boards.

= AMI for AMI 386 motherboard.= G23 for G2 386 board.= ??? other n/a.

NNNN = reference number for manufacturer.MMDDYY = BIOS release date.KX = AMI keyboard BIOS version number (X = usually

1,2,3,etc).

(could someone provide information for recent BIOS serial numbers?)

c) Display memory count. You will also ear tick sounds if you haveenabled it (see Memory Test Tick Sound section).

d) Once the POST have succeeded and the BIOS is ready to call theoperating system (DOS, OS/2, NT etc...) you will see a basic table of thesystem's configurations:

Main Processor: The type of CPU identified by the BIOS.Usually Cx386DX, Cx486DX, etc..

Numeric Processor: Present if you have a FPU or None on thecontrary. If you have a FPU and the BIOSdoes not recognize it, see section NumericProcessor Test in Advanced CMOS Setup.

Floppy Drive A: The drive A type. See section Floppy driveA in Standard CMOS Setup to alter thissetting.

Floppy Drive B: Idem.

Display Type: See section Primary display in StandardCMOS Setup.

AMIBIOS Date: The revision date of your AMI BIOS.Useful to mention when you havecompatibility problems with adaptor cards(notably fancy ones).

Base Memory Size: The number of KB of base memory.Usually 640.

Ext. Memory Size: The number of KB of extended memory.

NOTE: In the majority of cases, the summation of base memory andextended memory does not equal the total system memory. For instancein a 4096 KB (4MB) system, you will have 640KB of base memory and3072KB of extended memory, a total of 3712KB. The missing 384KB isreserved by the BIOS, mainly as shadow memory (see Advanced CMOSSetup).

Hard Disk C: Type: The master HDD number. See Hard diskC: type section in Standard CMOS Setup.

Hard Disk D: Type: The slave HDD number. See Hard disk D:type section in Standard CMOS Setup.

Serial Port(s): The hex numbers of your COM ports. 3F8and 2F8 for COM1 and COM2.

Parallel Port(s): The hex number of your LTP ports. 378for LPT1.

Right under the table, BIOS usually display the size of cache memory.Common sizes are 64KB, 128KB or 256KB. See External Cache Memorysection in Advanced CMOS Setup.



2.2 AMI BIOS POST Errors------------------------------During the POST routines, which are performed each time the system ispowered on, errors may occur. Non-fatal errors are those which, in mostcases, allow the system to continue the boot up process. The errormessages normally appear on the screen. Fatal errors are those which will

not allow the system to continue the boot-up procedure. If a fatal erroroccurs, you should consult with your system manufacturer or dealer forpossible repairs. These errors are usually communicated through a seriesof audible beeps. The numbers on the fatal error list correspond to thenumber of beeps for the corresponding error. All errors listed, with theexception of #8, are fatal errors. All errors found by the BIOS will be putinto I/O port 80h.

# of Beeps Meaning1 DRAM refresh failure. The memory refresh circuitry on

the motherboard is faulty.2 Parity Circuit failure. A parity error was detected in the

base memory (first 64k Block) of the system.3 Base 64K RAM failure. A memory failure occuredwithin the first 64k of memory.

4 System Timer failure. Timer #1 on the system board hasfailed to function properly.

5 Processor failure. The CPU on the system board hasgenerated an error.

6 Keyboard Controller 8042-Gate A20 error. Thekeyboard controller (8042) contains the gate A20 switchwhich allows the computer to operate in virtual mode.This error message means that the BIOS is not able toswitch the CPU into protected mode.

7 Virtual Mode (processor) Exception error. The CPU on

the motherboard has generated an Interrupt Failureexception interrupt.

8 Display Memory R/W Test failure. The system videoadapter is either missing or Read/Write Error its memoryis faulty. This in not a fatal error.

9 ROM-BIOS Checksum failure. The ROM checksumvalue does not match the value encoded in the BIOS.This is good indication that the BIOS ROMs went bad.

10 CMOS Shutdown Register. The shutdown register for theCMOS memory Read/Write Error has failed.

(*)11 Cache Error / External Cache Bad. The external cacheis faulty.

2.3 Other AMI BIOS POST Codes------------------------------2 short beeps: POST failed. This is caused by a failure of one of the

hardware testing procedures.

1 long & 2 shortbeeps: Video failure. This is caused by one of two possible

hardware faults. 1) Video BIOS ROM failure,checksum error encountered. 2) The video adapterinstalled has a horizontal retrace failure.

1 long & 3 short

beeps: Video failure. This is caused by one of three possiblehardware problems. 1) The video DAC has failed. 2)the monitor detection process has failed. 3) The video



RAM has failed.

1 long beep: POST passed. This indicates that all hardware testswere completed without encountering errors.

If you have access to a POST Card reader, (Jameco, etc) you can watch thesystem perform each test by the value that's displayed. If/when the system

hangs (if there's a problem) the last value displayed will give you a goodidea where and what went wrong, or what's bad on the system board. Ofcourse, having a description of those codes would be helpful, and differentBIOSes have different meanings for the codes. (could someone point outFTP sites where we could have access to a complete list of error codes fordifferent versions of AMI BIOS?).

(*)2.4 BIOS Error Messages------------------------------This is a short list of most frequent on-screen BIOS error messages. Yoursystem may show them in a different manner. When you see any of these,you are in trouble - Doh! (Does someone has any additions of

corrections?)

"8042 Gate - A20 Error" : Gate A20 on the keyboard controller(8042) is not working.

"Address Line Short!" : Error in the address decoding circuitry."Cache Memory Bad,Do Not Enable Cache!" : Cache memory is defective."CH-2 Timer Error" : There is an error in timer 2. Several

systems have two timers."CMOS Battery State Low" : The battery power is getting low. It

would be a good idea to replace the battery."CMOS Checksum Failure" : After CMOS RAM values are saved, a

checksum value is generated for error

checking. The previous value is differentfrom the current value.

"CMOS System OptionsNot Set" : The values stored in CMOS RAM are

either corrupt or nonexistent."CMOS Display TypeMismatch" : The video type in CMOS RAM is not the

one detected by the BIOS."CMOS Memory SizeMismatch" : The physical amount of memory on the

motherboard is different than the amount inCMOS RAM.

"CMOS Time and DateNot Set" : Self evident."Diskette Boot Failure" : The boot disk in floppy drive A: is corrupt

(virus?). Is an operating system present?"Display Switch NotProper" : A video switch on the motherboard must

be set to either color or monochrome."DMA Error" : Error in the DMA controller."DMA #1 Error" : Error in the first DMA channel."DMA #2 Error" : Error in the second DMA channel."FDD Controller Failure" : The BIOS cannot communicate with the

floppy disk drive controller."HDD Controller Failure" : The BIOS cannot communicate with the

hard disk drive controller."INTR #1 Error" : Interrupt channel 1 failed POST."INTR #2 Error" : Interrupt channel 2 failed POST.



"Keyboard Error" : There is a timing problem with thekeyboard.

"KB/Interface Error" : There is an error in the keyboardconnector.

"Parity Error ????" : Parity error in system memory at anunknown address.

"Memory Parity Error

at xxxxx": : Memory failed at the xxxxx address."I/O Card Parity Errorat xxxxx": An expansion card failed at the xxxxx

address."DMA Bus Time-out" : A device has used the bus signal for more

than allocated time (around 8microseconds).

NOTE: If you encounter any POST error, there is a good chance that itis an HARDWARE related problem. You should at least verify if adaptorcards or other removable components (simms, drams etc...) are properlyinserted before calling for help.

3.0 STANDARD CMOS SETUP==================================WARNING: You should have your current setup options written downON PAPER somewhere, preferably taped to the inside or the outside ofthe case. CMOS memory has a tendency to get erased as the battery getsold, or become inaccessible if you forget the password. Especiallyremember the hard disk settings; they are the most important.

NOTE: There are several good CMOS saver programs out on the market,including the PC-Tools and Norton recovery programs. They allow a userto save a copy of the CMOS registers to a file in case the battery dies, or they

mess around with the settings, etc...

Date (mn/date/year) : To change the date of the system clock.Time (hour/min/sec) : To change the time of the system clock.

Hard disk C:type : The number of your primary (master) hard drive.

Most of the time this number is 47, which means thatyou must specify the drive specs according to your harddrive manual:Cyln : The number of cylinders on your hard disk.Head : The number of heads.WPcom : Write Precompensation. Older HDD's havethe same number of sectors per track at the innermosttracks as at the outhermost tracks. This means that thedata density at the innermost tracks is higher and thusthe bits are lying closer together. Normally the data iswritten like this:

+ + - + - + + + - - - +Areas having the same direction tend to float away fromeachother and areas having opposite direction tend tofloat towards eachother:

+ + - + - + + + - - - +making the data less reliable after some time. To avoidthis, starting from the WP cylinder, bits are written on

the surface like this:+ + - + - + + + - - - +

making your data last longer. Starting with this Cyl#



until the end of Cyl#s the writing starts earlier on thedisk. In modern HDs (all AT-BUS and SCSI, SmallComputer Systems Interface) this entry is useless. Setit either to -1 or max Cyln. For IDE (Integrated DeviceElectronics) HDD's it is not necessary to enter a WPcylinder. The IDE HDD will ignore it for it has its ownparameters aboard.

LZone : The address of the landing zone. Same asWPcom. Used in old HDs without an auto-parkingfeature (MFM, Modified Frequency Modulated, orRLL, Run Length Limited). Set it to 0 or max Cyl#.Sect : The number of sectors per track.Size : This is automatically calculated according thenumber of cylinders, heads and sectors. It is inmegabytes.

NOTE: There is a shareware program called ANYDRIVE that will allowyou to set up hard drive geometries not supported in your BIOS. Thisshould be available on your favourite local BBS (Any internet FTP site for

this one?). Note that it only sets the correct geometry, many older BIOSeshave timing problems with IDE drives and this type of problem will notbe helped by ANYDRIVE. (*) You can also use the freeware programHD-MBOOT from the archive file DSUTIL12.ZIP on the Internet:SIMTEL20 or its mirrors, and GARBO FTP-sites in the directory/MSDOS/TURBOPAS or PC/TURBOPAS.

Hard disk D:type : The number of your secondary (slave) hard drive.

Same procedure than above. Jumpers must be set for anhard drive to perform as slave. Please refer to yourhard drive manual. You might also want to refer to the

hard disk data file frequently posted tocomp.sys.ibm.pc.hardware.

Floppy drive A : The type of floppy drive installed for drive A.Frequent configurations are 1.44 MB (3 1/2 inches), or1.2 MB (5 1/4). Newer systems have also a 2.88 MB(3 1/2) setting.

Floppy drive B : The type of floppy drive installed for drive B.

Primary display : The type of displaying standard you are using. Themost frequent is VGA/PGA/EGA. Modern computershave VGA (Video Graphics Array). If you have anolder black/white display select Mono or Hercules, ifyour Video adapter card is text only, select MDA.

Keyboard : Installed. If 'not installed' this option sets the BIOS topass the keyboard test in the POST, allowing to reset aPC without a keyboard (file server, printer server, etc.),without the BIOS producing a keyboard error.

4.0 ADVANCED CMOS SETUP==================================WARNING: May vary according to your system and your BIOS version.Some functions may not be present or the order and name may be

different.ADDITIONAL WARNING: Know *exactly* what you are doing. Someconfigurations may keep your computer off from booting. If that's the



case: Switch the power off. Turn your computer on *while* keeping theDEL key pressed. Some mainboards will come up again. If it still doesn'tboot, consult your motherboard manual. Look for a "forget CMOSRAM" jumper. Set it. Try it again. If it still doesn't boot, ask a friendor post to this newsgroup. You are permitted to panic. See note in section3.0.

Typematic RateProgramming : Disabled. It enables the typematic rate

programming of the keyboard. Not allkeyboards support this! The following twoentries specify how the keyboard isprogrammed if enabled.

Typematic Rate Delay(msec) : 500. The initial delay before key

auto-repeat starts. I.e. how long you'vegot to press a key before it starts repeating.

Typematic Rate (Chars/Sec) : 15. It is the frequency of the auto-repeati.e. how fast a key repeats.

Above 1 MB Memory Test : If you want the system to check thememory above 1 MB for errors. Disabledrecommended for faster boot sequence.The HIMEM.SYS driver for DOS 6.2 nowverifies the XMS (Extended MemorySpecification), so this test is redundant.Alternatively, you can enable this test anddisable HIMEM.SYS from doing so. (*) Itis preferrable to use the XMS test providedby HIMEM.SYS since it is operating in the

real environment (where user wait statesand other are operational).

Memory Test Tick Sound : Enabled recommended. It gives an audiorecord that the boot sequence is workingproperly. Plus, it's aural confirmation ofyour CPU clock speed/Turbo switch setting(for trained users!).

Memory Parity ErrorCheck : Enabled recommended. Additional feature to test bit

errors in the memory. All (or almost all) PC's checktheir memory during operation. Every byte in memoryhas another ninth bit, that with every write access is setin such way that the parity of all bytes is odd. Withevery read access the parity of a byte is checked for thisodd parity. If a parity error occurs, the NMI (NonMaskable Interrupt), an interrupt you mostly cannotswitch off, so the computer stops his work and displaysa RAM failure) becomes active and forces the CPU toenter an interrupt handler, mostly writing somethinglikes this on the screen: PARITY ERROR AT0AB5:00BE SYSTEM HALTED. On somemotherboards you can disable parity checking withstandard memory. Enabled to be sure data from

memory are correct. Disable only if you have 8-bitRAM, which some vendors use because it's 10%cheaper. If you own a Gravis Ultrasound Soundcard



(GUS), it's imperative that this is enabled; otherwise theSound Blaster emulation won't work(!).

Hard Disk Type 47RAM Area : The BIOS has to place the HD type 47 data

somewhere in memory. You can choose between DOSmemory or PC BIOS (or peripheral card) memory area

0:300. DOS memory is valuable, you only have 640KBof it. So you should try to use 0:300 memory areainstead. There may be some peripheral card whichneeds this area too (soundcard, network, whatever). Soif there are some fancy cards in your PC, check themanuals if they're using the 0:300 area. But in mostcases this will work without checking. (*) This isredundant if BIOS is shadowed (may be not in very oldBIOSes). The RAM area can be verified by checkingaddress of int41h and int46h. These are fixed diskparameters blocks. If they point to the BIOS area, BIOSmade modification of parameters before mapping RAM

there.

Wait for IfAny Error : When the boot sequence encounter an error it

asks you to press F1. Only at 'non-fatal' errors.If disabled, system print warning and continues toboot without waiting for you to press any keys.Enabled recommended.

System Boot Up NumLock : Specify if you want the Num Lock key to be

activated at boot up. Some like it, some do not.MS-DOS (starting with 6.0, maybe earlier)

allows a "NUMLOCK=" directive in config.sys,too; if someone turns the BIOS flag off but hasNUMLOCK=ON in their configuration file, theymay be a bit perturbed.

Numeric ProcessorTest : Enabled if you have a math coprocessor (built in

for the 486DX and 486DX2 family). Disabled ifyou don't (386SX, 386DX, 486SX, 486SLC and486DLC). If disabled, your FPU (Floating PointUnit, if present) isn't recognized as present by thesystem.

Weitek Coprocessor : If you have Weitek FPU, enable. If youhaven't, disable. Weitek uses some RAM addressspace, so memory from this region must beremapped somewhere else.

Floppy Drive Seek at Boot : Power up your A: floppy drive at boot.Disabled recommended for faster bootsequence and for reduced damage of heads.

System BootSequence : What drive the system checks first for an operating

system. C:, A: recommended for faster boot sequence,

or to not allow any user to enter your system by bootingfrom the FDD if your autoexec.bat starts with a loginprocedure. A:, C: if the person who uses the computer



is someone who don't knows how to setup CMOS.Because if something fails and a boot floppy won'twork, many users won't know what to do next.However, be careful. You had better know this settingis turned on and be prepared to turn it off if your harddisk boot track becomes corrupted, but not obviouslyabsent, since you otherwise won't be able to boot from

floppy. Also, it's easy to fool yourself into thinking youbooted from a known virus-free floppy when it actuallybooted from the (virus-infested) hard drive.

System Boot UpCPU speed : Specify at what processor speed the system will boot

from. Usual settings are HIGH and LOW. HIGHrecommended. If you encounter booting problems, youmay try LOW.

External CacheMemory : Enabled if you have cache memory. This is a frequent

error in CMOS setup. If Disabled when you have cachememory, the system performance decreasessignificantly. Most systems have from 64 to 256KB ofexternal cache. It is a cache between the CPU and thesystem bus. If Enabled when the system does not havecache memory, the system will freeze most of the time.

Internal CacheMemory : Enable or disable the internal cache memory of the

CPU. Disabled for 386 and Enabled for 486 (1 to 8KBof internal CPU cache). If the CPU does not haveinternal cache, the system may freeze if enabled.

NOTE: In many AMI BIOSes, the two previous options are implementedeither as separate Internal and External Enable/Disable options, or as asingle option (Cache Memory : Disabled/Internal/Both).

Fast Gate A20 Option : A20 refers to the first 64KB of extented memory(A0 to A19) known as the "high memory area".This option uses the fast gate A20 line, supportedin some chipsets, to access memory above 1 MB.Normally all RAM access above 1 MB is handledthrough the keyboard controller chip. Using thisoption will make the access faster than the normalmethod. This option is very useful in networkingoperating systems.

Shadow MemoryCacheable : You increase speed by copying ROM to RAM.

Do you want to increase it by cacheing it? Yes orno - see Video BIOS Area cacheable. Yesrecommended.

Password CheckingOption : Setup password to have access to the system and

/ or to the setup menu. Good if the computer is tobe shared with several persons and you don't wantanyone (friends, sister etc...) to mess up with the

BIOS. Default password: AMI (if you have AMIBIOS). Award: BIOSTAR (Note: I even know acomputer store that kept standard award BIOS



configuration with their systems because theydidn't know what the award default passwordwas!).

Video ROM ShadowC000,16K : Memory hidden under the "I/O hole" from 0x0A0000

to 0x0FFFFF may be used to "shadow" ROM (Read-

Only Memory). Doing so, the contents of the ROM arecopied into the RAM and the RAM is used instead.Video BIOS is stored in slow EPROM (ErasableProgrammable Read-Only Memory) chips (120 to 150nsof access time). Also, ROM is 8 or 16 bit while RAM32 bit wide access. With Shadow on, the EPROMcontent is copied to RAM (60 to 80ns of access timewith 32 bit wide access). Therefore perfomanceincreases significantly. Only sensible on EGA/VGAsystems. Enabled recommended. If you have flashBIOS, you can disabled it. Flash BIOS enable access atspeeds similar to memory access so you can use the

memory elsewhere. However, flash BIOS is still onlyaccessing it at the speed of the bus (ISA, EISA orVLB). On systems where the BIOS automatically steals384k of RAM anyway, it shouldn't hurt to enableshadowing even on flash ROM. One side effect is thatyou will not be able to modify the contents of flashROM when the chip is shadowed. If you reconfigure anadapter which you think might have flash ROM, andyour changes are ignored, or of course if it gives you anerror message when you try to change them, you'll needto temporarily disable shadowing that adapter. On(S)VGA you should enable both video shadows. Somevideo cards maybe using different addresses than C000

and C400. If it is the case, you should use suppliedutilities that will shadow the video BIOS, in which caseyou should disable this setting in the CMOS. VideoBIOS shadowing can cause software like XFree86 (thefree X Window System) to hang. They should beprobably be disabled if you run any of the 386 unixes.

NOTE: Some cards map BIOS or other memory not only in the usuala0000-fffff address range, but also just below the 16MB border or at otherplaces. The BIOS (for PCI buses only?) now allows to create a hole in theaddress range where the card sits. The hole may be enabled by giving anaddress, then a size is requested in power of 2, 64k - 1MB.

Video ROM Shadow C400,16K : Same than previous, except it is foranother segment of video memory.Enabled recommended.

Adaptor ROM ShadowC800,16K : Disabled. Those addresses (C800 to EC00) are

for special cards, e.g. network and controllers.Enable only if you've got an adapter card withROM in one of these areas. It is a BAD idea touse shadow RAM for memory areas that aren'treally ROM, e.g. network card buffers and othermemory-mapped devices. This may interfere

with the card's operation. To intelligently setthese options you need to know what cards usewhat addresses. Most secondary display cards



(like MDA and Hercules) use the ROM C800address. Since they are slow, shadowing thisaddress would improve their performance. Anadvanced tip: in some setups it is possible toenable shadow RAM *without* write-protectingit; with a small driver (UMM) it is then possibleto use this 'shadow RAM' as UMB (Upper

Memory Block) space. This has speed advantagesover UMB space provided by EMM386.

Adaptor ROM Shadow CC00,16K : Disabled. Some hard drive adaptersuse that address.

Adaptor ROM Shadow D000,16K : Disabled. D000 is the defaultAddress for most Network InterfaceCards.

Adaptor ROM Shadow D400,16K : Disabled. Some special controllersfor four floppy drives have a BIOSROM at D400..D7FF.

Adaptor ROM Shadow D800,16K : Disabled

Adaptor ROM Shadow DC00,16K : DisabledAdaptor ROM Shadow E000,16K : Disabled. E000 is a good "out ofthe way" place to put the EMS pageframe. If necessary.

Adaptor ROM Shadow E400,16K : DisabledAdaptor ROM Shadow E800,16K : DisabledAdaptor ROM Shadow EC00,16K : Disabled. SCSI controller cards

with their own BIOS could beaccalerated by using Shadow RAM.Some SCSI controllers do have someRAM areas too, so it depends on thebrand.

NOTE: Some SCSI adapters do not use I/O-Adresses. The BIOS addressrange contains writable addresses, which in fact are the I/O-ports. Thismeans: this address must not be shadowed and even not be cached.

System ROM Shadow F000,64K : Same thing as Video shadow, butaccording to the system bios (maincomputer BIOS). Enabledrecommended for improvedperformance. System BIOSshadowing and caching should bedisabled to run anything but MSDOS.

NOTE: On some BIOS versions (probably newer ones) the shadowchoices are in 800(hex)-byte increments. For instance, instead of twoVideo ROM Shadow segments of 16K (C400 and C800), you will haveone 32K segment. Same thing for Adaptor ROM Shadow segments.

BootSector VirusProtection : It is not exacly a virus protection. All it does is

whenever your boot sector is accessed for writing, itgives a warning to the screen allowing you to disable theaccess or to continue. Extremely annoying if you usesomething like OS/2 Boot Manager that needs to writeto it. It is completely useless for SCSI or ESDI(Enhanced Small Device Interface) drives as they use

their own BIOS on the controller. Disabledrecommended. If you want virus protection, use a TSR(Terminate and Stay Resident) virus detection (Norton,



Central Point, etc...). Scan by Macfee is also a goodidea. Available on most FTP servers, it is a shareware.

5.0 ADVANCED CHIPSET SETUP==================================WARNING: May vary according to your system and your BIOS version.Be sure of what you are doing!

Hidden Refresh : Allows the RAM refresh memory cycles to take placein memory banks not used by your CPU at this time,instead or together with the normal refresh cycles,which are executed every time a certain interrupt(DRQ0 every 15 msecs) is called by a certain timer(OUT1). Every time it takes 2 to 4 msecs for therefresh. One refresh cycle every ~16 us refreshes 256rows in ~ 4ms. Each refresh cycle only takes theequivalent of one memory read or less, as CAS(Column Address Strobe) is not needed for a refreshcycle. Some RAMs can do it, some not. Try. If the

computer fails, turn it off. Enabled recommended.There are typically 3 types of refresh schemes: cycle steal,cycle stretch, or hidden refresh. Cycle steal actually stealsa clock cycle from the CPU to do the refresh. Cyclestretch actually delays a cycle from the processor to dothe refresh. Since it only occurs every say 4ms or so, it'san improvement from cycle steal. We're not reallystealing a cycle, only stretching one. Hidden refreshtypically doesn't stretch or steal anything. It's usually tiedto DTACK (Data acknowledge) or ALE (Address LatchEnable) or some other signal relating to memory access.Since memory is accessed ALL of the time, ie ram, rom,etc. it's easy to synchronize the the refresh on the falling

edge of this event. Of course, the system performance isat its optimum efficiency, refresh wise sinces we're nottaking clock cycles away from the CPU.

Slow Refresh : Causes RAM refresh to happen less often than usual.This increases the performance slightly due to thereduced contention between the CPU and refreshcircuitry, but not all DRAMs necessarily support thesereduced refresh rates (in which case you will get parityerrors and crashes).

Concurrent Refresh : Both the processor and the refresh hardwarehave acces to the memory at the same time. Ifyou switch this off, the processor has to wait untilthe refresh hardware has finished (it's a lotslower). Enabled recommended.

Single ALE Enable : ALE (Address Latch Enable) is a pin on yourPC-bus that is active each time there is an addresson the bus. May slow the video bus speed isenabled. Still very obscure???

Keyboard Reset Control : Enable Ctrl-Alt-Del warm reboot.Enabled recommended for more controlover your system.

AT BUS ClockSelection : Gives a division of the CPU clock so it can reach the ISA -



EISA bus clock. An improper setting may cause significantdecrease in performance. The settings are in terms of CLK/x,(or CLKIN/x) where x may have values like 2, 3, 4, 5, etc.CLK represents your processor speed, with the exception thatclock-multiple processors need to use the EXTERNAL clockrate, so a 486DX33, 486DX2/66, and 486DX3/99 all count as33. You should try to reach 8.33 Mhz (that's the old bus

clock of IBM AT; there may be cards which could do higher,but it's not highly recommended). On some motherboards,the AT bus speed is 7.15 Mhz. On new BIOS versions, thereis an AUTO setting that will look at the clock frequency anddetermine the proper divider.

CPU Speed Appropriate setting16 CLK/225 or DX2/50 CLK/333, DX2/66 or DX3/99 CLK/440 or DX2/80 CLK/550 or DX2/100 CLK/6

You can try other settings to increase performance. If you

choose a too small divider (CLK/2 for a DX33) your systemmay hang. For a too big divider (CLK/5 for a DX33) theperformance of ISA cards will decrease. This setting is fordata exchange with ISA cards, NOT VESA cards which runat CPU bus clock speeds: 25Mhz, 33Mhz and higher. If yourISA cards are fast enough to keep up, it is possible to run thebus at 12 Mhz. Note that if you switch crystals to overclockyour CPU, you are also overclocking the ISA bus unless youchange settings to compensate. Just because you canoverclock the CPU doesn't mean you can get away withoverclocking the ISA bus. It might just be one card thatcauses trouble, but one is enough. It might cause trouble evenif you aren't using it by responding when it shouldn't.

Fast AT Cycle : If enabled, may speed up transfer rates with ISAcards, notably video. ???

Fast DecodeEnable : Refers to some hardware that monitors the commands sent

to the keyboard controller chip. The original AT used specialcodes not processed by the keyboard itself to control theswitching of the 286 processor back from protected mode toreal mode. The 286 had no hardware to do this, so theyactually have to reset the CPU to switch back. This was nota speedy operation in the original AT, since IBM neverexpected that an OS might need to jump back and forthbetween real and protected modes. Clone makers added a fewPLD chips to monitor the commands sent to the keyboardcontroller chip, and when the "reset CPU" code was seen, thePLD chips did an immediate reset, rather than waiting for thekeyboard controller chip to poll its input, recognize the resetcode, and then shut down the CPU for a short period. This"fast decode" of the keyboard reset command allowed OS/2and Windows to switch between real and protected modefaster, and gave much better performance. (early 286 cloneswith Phoenix 286 BIOS had this setting to enable/disable thefast decode logic.) On 386 and newer processors, the fastdecode is probably not used, since these CPUs have hardware

instructions for switching between modes. There is anotherpossible definition of the "Fast Decode Enable" command.The design of the original AT bus made it very difficult to mix



8-bit and 16-bit RAM or ROM within the same 128K block ofhigh address space. Thus, an 8-bit BIOS ROM on a VGAcard forced all other peripherals using the C000-Dfff range toalso use 8 bits. By doing an "early decode" of the highaddress lines along with the 8/16 bit select flag, the I/O buscould then use mixed 8 and 16 bit peripherals. It is possiblethat on later systems, this BIOS flag controls the "fast decode"

on these address lines.

Extended I/O Decode : The normal range of I/O addresses is 0-0x3ff;10 bits of I/O address space. ExtendedI/O-decode enables wider I/O-address bus. TheCPU(s) support a 64K I/O space, 16 addresslines. Most motherboards or I/O adapters can bedecoded only by 10 address bits.

(*)I/O Recovery Time : When enabled, more I/O wait states areinserted. A transfer from IDE harddrive tomemory happens without any handshaking,

meaning the data has to be present (in the cacheof the harddisk) when the CPU wants to readthem from an I/O Port. This is called PIO(Programmed I/O) and works with a REP INSWassembler instruction. Now I/O Recovery Timeenabled adds some wait states to this instruction.When disabled, the harddrive is a lot faster. Notethat there is a connection between I/O RecoveryTime and AT BUS Clock Selection. Forexample, if the AT BUS Clock is set to 8 MHZand you have a normal harddisk, I/O RecoveryTime can be turned off, resulting in a highertransfer rate from harddisk.

Memory ReadWait State : Wait states is for RAM which aren't fast enough for

the computer. On a 486, 1 or more wait states are oftenrequired for RAM with 80ns or higher access time.And, depending on the processor and motherboard, alsofor lower than 80ns access time. The less wait states,the better. Consult your manual. If wait states are toolow, a parity error will occur. For 386 or 486non-burst memory access cycle takes 2 clock ticks. A*rough* indication of RAM speed necessary for 0 waitstates is 2000/Clock[MHz] - 10 [ns]. For a 33Mhzprocessor, this would give 50ns of access time required.The number of wait states necessary is *approximately*(RamSpeed[ns] +10) * Clock[MHz] /1000 - 2. For70ns RAM and a 33Mhz processor (very standardconfiguration), this would give roughly 1 wait state.But this really is dependent on chipset, motherboard andcache design, CPU type and whether we talk aboutreads or writes. Take these formulas with a large grainof salt. You can find out the access time of your RAMchips by looking at their product numbers. Mostly atthe end there is a 70, 80, 90, or even 60. If 10 standsthere, it means 100 ns. Some RAM chips also have anexplicitly written speed in ns. The RAM you buy these

days mostly have 70ns or 60ns.

Memory Write Wait State : Same as above.



Note: In some BIOSes, these two options are combined as 'DRAM WaitState'. In that case, the number of read & write wait states is necessarilyequal.

Post Write Control : ???

CAS Pulse Width : Column Address Strobe. A DRAM parameter.???

RAS Precharge Time : Row Address Strobe. ???

RAS to CAS Delay : ???

Cache Read Option : Often also "SRAM Read wait state", (SRAM:Static Random Access Memory) taking simpleinteger values, or "SRAM Burst", taking 2-1-1-1,3-1-1-1 or 3-2-2-2. This determines the numberof wait states for the cache RAM in normal and

burst transfers (the latter for 486 only). Thelower you computer can support, the better.

Cache Write Option : Same thing as memory wait states, but accordingto cache ram.

Non-CacheableBlock-1 Size : Disabled. The Non-Cacheable region is intended for

a memory-mapped I/O device that isn't supposed to becached. For example, some video cards can present allvideo memory at 15 meg - 16 meg so software doesn'thave to bank-switch. If the non-cacheable region coversactual RAM memory you are using, expect a significant

performance decrease for accesses to that area. If thenon-cacheable region covers only non-existent memoryaddresses, don't worry about it. If you dont want tocache some memory you can exclude 2 regions ofmemory. There are *good* reasons not to cache somememory areas. For example, if the memory areacorresponds to some kind of buffer memory on a cardso that the card may alter the contents of this bufferwithout warning the cache to invalidate thecorresponding cache lines. Some BIOSes take moreoptions than enabled /disabled, namely Nonlocal/Noncache /Disabled (VLB only?).

Non-Cacheable Block-1 Base : 0KB. Enter the base address of thearea you don't want to cache.

Non-Cacheable Block-2 Size : Disabled.Non-Cacheable Block-2 Base : 0KB.Cacheable RAMAddress Range : Usually chipsets allow memory to be cached just up to

16 or 32 MB. This is to limit the number of bits of amemory address that need to be saved in the cachetogether with its contents. If you only have 4MB ofRAM, select 4MB here. The lower the better, don'tenter 16MB if you only have 8MB installed!

Video BIOS AreaCacheable : To cache or not to cache video BIOS. You should try

what is better - video access is faster with 'enabled', but



cache has its size. With an "accelerated" video card itmay be necessary to make the video RAM regionnon-cacheable so the CPU can see any changes thedrawing engine makes in the frame buffer.

6.0 AUTO CONFIGURATION WITH BIOS DEFAULTS==================================

The BIOS defaults are the ones that are tuned for yourmotherboard/chipset, but give a reasonable chance of getting into POST.Usually these settings are a good start to fine tune your system. If you didsomething wrong and don't know what, select this. It will replace yourBIOS settings by default values. You will have to start all over again. Besure to know your system's configuration. This option does *not* alterthe date and harddisk & floppy disk configuration in the Standard CMOSsetup, so in general you can expect your system to boot without problemsafter selecting this.

7.0 AUTO CONFIGURATION WITH POWER-ON DEFAULTS==================================

When powering on, the BIOS puts the system in the most conservativestate you can think of. Turbo off, all caches disabled, all wait states tomaximum, etc... This is to make sure that you can always enter BIOSsetup. Useful if the settings obtained by selecting AUTOCONFIGURATION WITH BIOS DEFAULTS fail. If the system doesnot work with these values, it's time to panic: the problem maybehardware related (DIP switches, cards not inserted properly or worst,something broken).

8.0 CHANGE PASSWORD==================================Enable you to change the active password. The default is no password.WARNING: Remember your password!!! Write it down somewhere!!!

Ask yourself: Do I really need to set a password to access my systemand/or the BIOS? (is your brother/sister/kid/employee that dangerous?) Ifsecurity is of some minor concern to you, disabled recommended. Whynot only password protect (or encrypt) some critical files (personalfinances, juicy love letters, client information databases, etc...)? If youlose your password, you will have to erase your CMOS memory (seeFAQ).

9.0 HARD DISK UTILITY==================================9.1 Hard Disk Format------------------------------Will format your hard disk so it can receive new partitions. WARNING:IT WILL SMASH EVERYTHING ON YOUR HARD DISK!!! USEWITH CAUTION. I lot of inexperienced users have lost their sanity withthis one. Several computer stores have made extra money with it!There's no need to do this unless you experience errors or if you want tochange the interleave. DON'T TOUCH THIS IF YOU'VE GOT AN IDEDRIVE. It will perform a low level format and probably SCRAP yourIDE hard drive. IDE means AT-Bus, the standard drive type nearlyeveryone has now. Also SCSI or ESDI drives shouldn't be low-levelformatted. The new drives actually don't perform the low level format,but some old AT-Bus (IDE) drives you can scratch with this... This entryis only sensible for old MFM or RLL hard disks! Please refer to your harddisk manual to see how or if your hard disk can be low level formatted.

Don't tell us we did not warn you.Many manufacturers provide utilities to low level format their IDE drives(or any other types). Please refer to the



comp.sys.ibm.pc.hardware.storage FAQ for more technical informationabout this procedure. If normal (high level) hard disk formatting isrequired, you can use DOS FDISK to first erase and create partitions andthen use FORMAT. It is also a good idea when you hard disk becomesunaccessible to see if it is just the system files that are corrupted. Most ofthe time, it is the case. SYS will do the job of replacing system files.Several packages (PC-Tools, Norton, etc...) provide utilities for repairing

"damaged" HDD and FDD. Therefore, low level format is always ofLAST RESORT when you encounter HDD problems.

9.2 Auto Detect Hard Disk------------------------------Handy when you "forgot" the specs of your hard drive. The BIOS willdetect the number of cylinders, heads and sectors on your hard disk.NOTE: In some BIOS versions, this option in the main SETUP menu.

9.3 Auto Interleave------------------------------Determines the optimum interleave factor for older hard disks. Some

controllers are faster than others, and you don't want the sectors laid outso reading consecutive sectors usually results in just missing the sector youwanted and having to wait a whole disk rotation for it to come aroundagain. On modern ones, it's always 1:1 (and even if it wasn't, you cannotreformat anyway).Interleaving is specified in a ratio, n:1, for small positive integers n.Basically, it means that the next sector on the track is located n positionsafter the current sector. The idea is that data on a hard drive might spinpast the heads faster than the adapter can feed it to the host. If it takes youmore than a certain amount of time to read a sector, by the time you'reready for the next sector, the heads will have passed it already. If this isthe case, the interleave is said to be "too tight". The converse, where the

CPU spends more time than necessary waiting for the next sector to spinunder the heads, is too "loose" of an interleave. Clearly, it is better tohave too loose an interleave than too tight, but the proper interleave isbetter still. Especially since any controller with read-ahead cacheing canpull the whole track into its buffer, no matter how slow the CPU is aboutfetching the data down.The 1:1 interleave arranges the sectors on a track as follows:0 1 2 3 4 5 6 7 8 9 a b c d e f g (17-sectors, using base 17 forconvenience, this is clearly the in-order arrangement, one after another)This is 2:1 interleaving:0 9 1 a 2 b 3 c 4 d 5 e 6 f 7 g 8The CPU has a whole sector's worth of time to get the a sector's datataken care of before the next sector arrives. It shows which logical sectorgoes in each physical sector.Anyway, an n:1 interleave restricts the transfer rate to 1/n the speed of a1:1 interleave (which is better than 1 revolution per sector if the interleaveis too tight!). No modern PC should require interleaving. Only MFM andRLL (maybe also ESDI) and floppy drives which are capable of it (youcould format a 1.44 meg floppy to 21 sectors/track, which would requirea 2:1 interleave to not exceed the 500 mbps speed of the controller...butwhy?).

9.4 Media Analysis.------------------------------Scan the hard disk for bad blocks. It is performing a LOW LEVEL

FORMAT on the track where bad sector is encountered to mark thatsector as a bad. It could cause damage on user data, even if scanningitself is non-destructive (also on MFM, RLL disks). Therefore, DON'T



USE this option to on AT-Bus (IDE), SCSI or ESDI drives. These drivesstore the bad block data themselves, so you don't have to tell them or scanthe media! Recommendation: use a media analysis program provided byan utility package or your hard drive manufacturer.

10.0 WRITE TO CMOS AND EXIT==================================

Save the changes you made in the CMOS. You must do that topermanently keep your configuration.

11.0 DO NOT WRITE TO CMOS AND EXIT==================================If you are not sure of the changes you made in the CMOS settings, use thisoption to exit safely.

12.0 FREQUENTLY ASKED QUESTIONS (FAQ)==================================1) How do I clear the BIOS memory?a) Disconnect battery.

b) Insert appropiate jumper (see mainboard documentation, near battery).Sometimes this is possible with DIP switches on the motherboard.Sometimes (if not), you will have to remove the battery. And sometimes(if no DIP's and no removable battery, and not willing to desolder thebattery), you can short the battery with a resistor to lower the currentavailable for the CMOS.This is only recommendable as a very last option. The NiCad cells oftenemployed have a very low internal resistance, so that the resistor will haveto be of very low value for the voltage to drop significantly. Thecorresponding current would be quite high, which is not very good forbattery life. A better option would be to use a resistor to discharge thebattery. Obviously, this only makes sense when you have a NiCad cell(which will be recharged every time you turn the computer on) as opposed

to a lithium cell (which cannot be recharged). In the former case, aresistor of 39 Ohm will discharge the battery in under half an hourrelatively safely.Another good way to discharge the NiCad is to put a 6 volt lantern lampacross it, and let it discharge completely. Not only does it provide aneffective load, it also gives a visual indication of the charge state. It's agoodway to prevent "ghost memory" that's so common to NiCads. Metal NickelHydride batteries are now being seen in some systems. They don't have thisproblem and they are more $$.

2) Can I upgrade my BIOS?Most BIOSes are specifically designed for a motherboard and its chipset.Therefore, on rare occasions you can upgrade your BIOS for a newerversion. It is often less troublesome to buy a new motherboard that comeswith its own BIOS and transfer your CPU (memory, cache memory andadaptor cards...) than start hunting around for a new BIOS chip. I knowvery few computer stores who sell BIOS chips separately. However, it ispossible to upgrade your BIOS so it may support new hardware. Bybrowsing in computer magazines (like Computer Shopper, PC Magazine,etc...) you will find adds on companies that specialize on that sort ofthing. The information they need is the Serial Number for the BIOS chip.It is the *long* number that prints out when you boot up. It includes theBIOS date, the chipset, etc. (see section 2.0). The price tag can varygreatly (from $10 to $80), so are the BIOS upgrades offered. (Does

anyone have supplementary information on this, like good-bad experienceswith BIOS upgrade? I already had 2 feedbacks on this, and they all aggreeit is a little tricky, but it works).



_________________________________________________________________

Note: I ([email protected]) did not write this survival guide. Refer to thecontributors or the editor (or post your question to usenet) if youhave any questions. Thanks..

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